Typical voltage converters convert an input voltage into an output voltage while the input voltage is different in level from the output voltage.
For example, Japanese Patent Application Publication No. 2011-15562, which will be referred to as a known patent document, discloses a power supply source including such a voltage converter. The voltage converter of the power supply source of the known patent document includes a first power supply unit and a second power supply unit; the first and second power supply units are connected in parallel to each other.
Each of the first and second power supply units has a function of converting an input voltage to a controlled output voltage, which is supplied to at least one electrical load.
The voltage converter of the known patent document is configured to determine how to drive the first and second power supply units depending on power required for the at least one electrical load.
Specifically, the voltage converter of the known patent document drives both the first and second power supply units when the voltage converter is in a high-load state. The voltage converter being in the high-load state means that the voltage converter should output, to at least one electrical load connected thereto, power that is not less than a predetermined level. In contrast, the voltage converter of the known patent document drives only the first power supply unit when the voltage converter is in a low-load state. The voltage converter is in the low-load state represents that the voltage converter should output, to at least one electrical load connected thereto, power that is less than the predetermined level.
The voltage converter of the known patent document aims to reduce power consumption loss of the voltage converter when the voltage converter is in the low-load state.